Growing Pains for the Large Breed Puppy
Oscar used to be a happy puppy. When his human parents first got him, he
looked like a little black and tan bear cub but he has since grown into a
gangly adolescent German Shepherd Dog. And he is no longer happy.
Instead of playing like a nine-month-old pup ought to, he limps on a front leg.
His owners could swear that last month it was the other front leg and they cannot
think of any way he might have injured himself playing. When they pick up the leg
to feel it, he cries sharply. He gets better for several weeks and then it starts
all over again. The vet has prescribed pain releivers for the bad days and has
told Oscar's owners that they must wait out this condition. Oscar has panosteitis.
Panosteitis, also referred to as "enostosis," "cosinophilic panosteitis," or simply
"panno," is an orthopedic disease of large breed pups generally 618 months
of age. The German Shepherd Dog is especially predisposed.
The disease stems from a proliferation of bone material inside the shafts of
the long bones of the legs. Any or all four legs can be affected. Sometimes the
lameness is accompanied by fever and general malaise and, after a flare-up, the
condition wanes only to recur a few weeks later in another leg. The diagnosis
is easy as bone proliferation shows up like a beacon on a radiograph but we still
do not know what causes this proliferation in the first place.
In 1960, a study was published in which bone marrow from dogs with panosteitis was injected
into bone marrow cavities of healthy dogs. The healthy dogs came down with
panosteitis within three weeks. This was strong evidence for an infectious
agent yet no bacteria have been cultured from lesions either in that study or since.
A virus would explain the ability to transmit the disease, the fact that some
dogs seem to get feverish with the disease, and the lack of other obvious
infectious agents, but it would not explain why small breed dogs are virtually
untouched by the disease. No virus has successfully been isolated from any dog
with panosteitis but the theory of viral infection is still very much alive
among researchers studying this condition.
The good news with panosteitis is that it is a disease of adolescence. By the
time patients like Oscar are two years old, the condition has almost always run its course.
There is no specific treatment other than medication to relieve pain and waiting for
adulthood to alleviate the condition.